Main slide-valve and throttle-valve for steam-engines



(No Model.) 2 Sheets-Sheet 1 J. P. DEVOISSAUD. vMAIN SLIDE VALVE ANDTHROTTLE VALVEI'OR STEAM ENGINES.

Patented Deer; 4, 1894;

/A/A/A/A////A// 342% NVENTOH A7TOBNEYS.

WITNESSES:

(No Model.) 2 Shets -Sheet,2.=

. JJP. DEVOISSAUD.

MAIN SLIDE VALVE AND THROTTLE-VALVE FOR STEAM ENGINES.

N0.530,400. "Patented 9904,1894? ATTORNEYS.

1 UMTED STATES JOHN P. DEVOISSAUD,

or SHERMAN, TEXAS.

MAIN SLIDE-VALVE AND THROTTLE-VALVE FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters PatentNo. 530,400, dated December4, 1894.

Application filed June 26,1894.

To all whom it may concern.-

Be it known that I, JOHN P. DEVOISSAUD; of Sherman, in the county ofGreyson and State of Texas, have invented a new and useful Improved MainSlide-Valve and Throttle-' Valve for Steam-Engines, of which thefollowing is a full, clean-and exact description.

.gine cylinders, which are horizontally disposed in the same verticalplane, said throttle valve being directly actuated by a suitablegovernor devicethat receives motion from the main shaft of the engine,whereby the throttle valve is adapted to control the transmission ofsteam that passes from the steam chest through the main valve and thencethrough the throttle valve into each, of the two cylinders, as thelatter is con trolled by the governor device.

A further object is to provide a co-acting, peculiarly constructedmainslide valve that, in conjunction with the novel throttle valve,afiords a complete and superior valve mechanism for a quick speed steamengineof the type indicated, or any other style forwhich said valves maybeap'plicable.

To these ends, my invention consists in the construction and combinationof parts, as is hereinafter described and claimed.

Reference is to be had to the accompanying drawings, forming a part ofthis specification,

in which similar figures of reference indicate corresponding parts inall the views shown.

Figure 1 is a sectional side view of the steam engine shown toillustrate theapplication of the improvements, and said valves inpositionthereon, the section being taken on the line'l-l in Fig. 2. Fig.2 is a partly sectional front view of the engine, with the improvedthrottle valve shown in position on it, by dotted lines, the sectionbeing on the line 22 in Fig. 1. Fig. 3 is'a sectional plan view of partsof the engine, the steam chest, main valve, its seat, and the improvedthrottle valve, on the line 3+3 in' Fig. 1; and Fig.

serial No. 515,749. on, model.)

4 is a side view of detached. A brief description of the steam engine onwhich the improved valves are especially well adapted for service, willbegiven to render clear their application and operation.

There is an elongated bed plate 10, provided, of a rectangular form,arranged in its details of construction to receive and support the twincylinders 11, in parallel horizontal planes at the front end'of said bedplate whereon the lower cylinder is aflixed. The cylinders 11 areintegrally constructed, and have a rearwardly closed exhaust passage 11,,formed in the wall that separates their bores, which similarcylindrical bores are forwardly :closed by the single head plate 11",and a lateral outlet 11 is formed in the cylinders "for the exhaustpassage 11 The piston .heads 12, are of approved construction notinternally shown, of the bucket type, having a pivoted connection withthe pair of connecting rods 13, Which pass through vertically elongatedslots 14 that are formed in the headvlt, which head is attached tothethe improved throttlo'valve *rear ends of the'cylinders.

The rods 13, are looselyjoined at their rear ;ends with. the transversejournal pins15 which serve to connect the end portions of 3 two similarupright rocking beams 15, the latiter being mounted an equal distancefrom their upper ends on the transverse shaft 15 5 said shaft having itsends journaled in boxes onthe bed plate 10, one of said beams and l theconnecting pinsand shaft mentioned,be-

\ ing represented in Fig. 1. v

On the bed plate 10, at its rear end, a transverse main shaft 16 isjournaled, having a double crank arm 16 formed on or secured to it at apoint which will allow the joining cross pin 16 of the arms 16?, to becoupled with the rear end ofth'e pitman 17, that is loosely securedatits forward end on. the cross pin 15, that is secured between therocking beams 15, at their lower ends, this connection of the cranks onthe main shaft adaptingthe alternate equal rearward movement of thepiston heads 12, to vibrate the beamsand rotate the main shaft.

channeled on its outer face at the transverse;

. 9 The cylinder head plate 11 is vertically V center, to receive theflat thin throttle valve 18, that will be hereinafter described. Thechannel mentioned having a suitable width, is rendered exactly levelthroughout its area on the bottom surface, which is also made parallelwith the rear surface of the cylinder head plate that is attached to theforward ends of the cylinders.

On the front side of the head-plate 11 that is true and parallel withits rear surface, except that a central projecting portion is formed onit as will be further explained, a main valve seat 19 is secured, and onsaid seat the rectangular steam chest 20 is imposed, it being true onfront and rear faces, and forming steam tight joints between it and thevalve seat it engages, as well as with the chest bonnet 20 that isdetachably held with the chest on the seat 19, a steam supply pipe 2Otapping one side of the chest for the introduction of live steamtherein. Aslight projection is formed on the inner surface of the bonnet20 at its transverse center extending vertically and inclined from itsupper edge downwardly and toward the valve seat 19, and as shown in Fig.1, a sufficient space intervenes this true surface to permit awedge-shaped presser block 21, to be introduced between the bonnet andthe adjacent surface of a main valve 22, the presser block havingatongue 21, on the rear face which has a loose engagement with acorresponding groove produced in the back of the main slide valve,provision being made for the adj ustable attachment of the presser blockon the bonnet with the bolts 2l which will adapt the valve 22 to have aproper contact of its working face with the main valve seat 19.

On the main crank shaft 16, at one side of the bed plate 10, an ordinaryeccentric 23 is secured, which has its strap connected to the eccentricrod 24 that extends forwardly to have its front end pivoted to the upperend of a rock arm 25, which is secured on the transverse rock shaft 26,that is journaled on the bed plate below the cylinders. At a suitablepoint from the rock arm 25, another rock arm 27 is affixed on the shaft26, and forwardly extends in a horizontal plane, its front end beingconnected by the pair of links 27 with the lower end of the dependingvalve rod 22, that is projected steam tight through the steam chest onits lower side, and has its upper end attached to the main valve 22.

The cylinder head plate 11 and main valve seat 19, are oppositely andtransversely slotted at two points near each end, thus affording twopairs of suitable spaced live steam ports 19, two of said portsintersecting each cylinder bore at points nearly equidistance from itslongitudinal axis, each live steam port being bisected by central bar asshown in Fig. 2.

At two points equally distance from the live steam ports that arenearest to the exhaust passage 11 two similar exhaust ports 19 areproduced in the cylinder head plate 11 and main valve seat 19, whichports extend from points near the side walls of the cylinders forwardly,and are preferably slightly converged toward their front ends, theybeing equally distance from a main exhaust port 19, that is formed inthe cylinder head and main valve seat opposite the exhaust passage 11,that said exhaust port intersects and thus establishes a continuousexhaust passage from the steam chest to the outer air at the side of thecylinders.

The main valve 22, has a cavity 22 formed in it at its longitudinalcenter of a width equal with the transverse dimensions of the mainexhaust port 19 and of such a length as will adapt it to connect saidmain exhaust port with either of the other exhaust ports 19 that tap thecylinders so that when the main valve is correctly adjusted and othermoving parts that actuate are properly arranged, the rotation of themain shaft 16 will cause the exhaust ports 19 to be alternately broughtinto direct connection with the main exhaust passage 11 for thedischarge of exhaust steam from the cylinders.

To adapt the main valve 22 to permit the passage of live steam from thechest 20, into the cylinders 11 it has two transverse steam ducts 22formed in it at a correct distance from its ends, and also from thecentral exmain valve 22, it is essential that its travelbe arranged, sothat one of the steam ports 19 in one cylinder willlbe uncovered at theadjacent end of the valve by said valve end, and the parallel andnearest port 19 be brought opposite the steam duct 22 at that end of themain valve, so'as to pass steam through the two steam ports 19 of thecylinder that is to receive live steam, while the similar ports for theother cylinder are covered by the main valve, a free passage for exhauststeam from the exhaust port in the last mentioned cylinder, beingsimultaneously produced by a proper connection of the exhaust cavity ofthe valve 22 with the main exhaust passage 19, and exhaust port 19 ofsaid cylinder, so that a sufficient pressure of steam in the chest willafford power to continuously and rapidly actuate the main shaft of theengine.

The most essential feature provided in this invention, is the peculiarthrottle valve 18, before mentioned, which consists of a fiatrectangular plate, having such proportionate dimensions, as will adaptit to fit steam tight in the channel formed to receive it inthe cylinderhead plate 11 and yet be permitted to freely slide in said channelendwise.

There are live steam ports transversely cut in the plate like throttlevalve 18, at such points as will allow them to coincide with the similarlive steam ports in the cylinder head plate and main valve seat thathave been already described. I

The center of the throttle valve 18 is rectangularly apertured of asufficient size to produce a large aperture 18 that loosely receives thecentral forward projection of the cylinder head plate 11 which latter isthereon formed to allow the ports.l9 .to be rendered continuous withtheir extensions in the valve seat 19. The aperture 18 in the throttlevalve is of a sufficient length to afford space of ample dimensionsabove and below the head plate projection mentioned, to permit the freereciprocation of the throttle valve, the expelled exhaust steam beingallowed to pass unrestrained through the exhaust ports 19 in the headplate 11 and the valve seat 19 without regard to the reciprocaladjustment of the said throttle valve.-

A flat stem 18 is projected from the upper end of the vertically locatedthrottle valve 18 which stem is at its upper terminal detach ablyconnected with the governor device 28 that is saddled on and secured tothe upper side of the top cylinder 11 atits forward end.

The governor preferably employed, is of an improved construction forwhich a patent has been allowed to me, and as it is not a part of thepresent invention a detailed description is not necessary.

Briefly considered the governor 28 consists of two flat disks centrallypivoted between laterally projectedarms of a yoke frame that iscentrally and loosely mounted on the bracket frame 28 each disk having aloose connection produced by a link between its edge that is nearest tothe vertical spindle 28 and said spindle, whereby the rocking movementof the disks on their pivot centers, will longitudinally move thespindle in accord with the degree of oscillation given to the disks.

Bevel gearing is arranged to rotate the yoke frame that supports thedisks and their Weights, one of said bevel wheels being secured ontheinner end of the horizontal shaft 28 that is rotatably supported onthe bracket frame 28, a pulley 28 that is affixed on the outer end ofthis shaft having a belted connection with a pulley 29 on the main shaftof the engine.

The operation of the throttle valve is as follows: It is so adjustedthat for a maximum load on the engine which requires full pressure ofsteam from the main valve 22, the ports in the throttle valve will bealigned with the live steam ports 19, so that the latter will be fullopen while the engine is thus working.

Should speed increase on account of increased steam pressure from theboiler, or a reductionof load on the engine, the more rapid rotation ofthe governor will depress the latter, and correspondingly actuate thethrottle, so as to diminish the openings in the live steam ports, whichwill thus control the working of the engine to secure a uniform speed,any increased load on the engine causing an opening of the steam portsin an obvious manner.

Having thus fully described my invention, I claim as new and desire tosecure by Letters Patent 1. In valves for a steam engine, thecombination of a throttle valve in plate form hetweeng a main slidevalve and two engine cyl inders, said valve being provided with acontral aperture and with live steam ports, and v a governor connectedwith said valve, substantially as described.

2. In valves for a steam engine, the combination with two cylindersprovided with a head having a projection thereon, said head having livesteam and exhaust ports therein,

a steam chest on the head anda slide valve in said steam chest, of athrottle valve in plate form, said valve being arranged in the head andprovided with acentral aperture to receive the projection of the saidhead, and with live steam ports registering with the live steam ports ofthe head, substantially as described.

3. In valves for a steam engine, the combination with two cylindersprovided with a head having a projection and provided with exhaust steamports in said projection and with two live steam ports at each side ofthe exhaust ports, of a valve casing in the head, a valve in the casingand provided with live steam and exhaust ports, and a throttle valve insaid head and having a central aperture to receive the said projectionand With two live steam ports ateach end, substantially as herein shownand described.

JOHN P. DEVOISSAUD.

Witnesses:

GEORGE OorTs, JOHN DOYLE.

